91991340 has 72 divisors (see below), whose sum is σ = 318907680. Its totient is φ = 21026304.

The previous prime is 91991323. The next prime is 91991359. The reversal of 91991340 is 4319919.

It is a hoax number, since the sum of its digits (36) coincides with the sum of the digits of its distinct prime factors.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 91991295 and 91991304.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 35245 + ... + 37764.

Almost surely, 2^91991340 is an apocalyptic number.

91991340 is a gapful number since it is divisible by the number (90) formed by its first and last digit.

It is an amenable number.

91991340 is an abundant number, since it is smaller than the sum of its proper divisors (226916340).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

91991340 is a wasteful number, since it uses less digits than its factorization.

91991340 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 73031 (or 73026 counting only the distinct ones).

The product of its (nonzero) digits is 8748, while the sum is 36.

The square root of 91991340 is about 9591.2116022951. The cubic root of 91991340 is about 451.4215784887.

The spelling of 91991340 in words is "ninety-one million, nine hundred ninety-one thousand, three hundred forty".